The overall objective of this research program is to examine the effects of time-variant proprioceptive and exteroceptive segmental inputs on the behavior of spinocerebellar systems and the responses which they evoke in specific regions of the cerebellar tract, the ventral spinocerebellar tract, the spino-reticulo-cerebellar projection and the newly described spino-neocerebellar pathways. The modifications of these responses produced by the action of an output system projecting from the neocerebellum, the dentato-bulbo-spinal system, as well as the reticulo-spino and raphe spinal system will also be determined. Furthermore, spatio-temporal features of integration occurring in the cerebellar cortex will be examined by the responses of 2-5 Purkinje cells in a given folium in response to proprioceptive and exteroceptive peripheral inputs. The behavior of these neurons will be assessed not only by observing changes in their excitability, but also changes in the degree to which the discharge of pairs of neurons are correlated. These studies include not only an electrophysiological evaluation of the excitability changes evoked by activating this projection but also an assessment of the contribution of this system to the overall characteristics of the response of Purkinje cells to time-variant proprioceptive and exteroceptive inputs.